In U.S. Pat. No. 4,776,331 entitled "Bandage," dated Oct. 11, 1988, there has been disclosed a bandage which includes pressure responsive means for providing an indication when the bandage applied to a part of a human body is too tight, causing pain. The pressure responsive means comprises a medium in sheet or strip from having encapsulated fluid, liquid or gas. The medium ruptures when a predetermined pressure is exceeded, thereby releasing the fluid. When the fluid comprises a liquid dye, the staining of the bandage provides a visual indication that a condition of excessive pressure is present.
It is now disclosed to use substantially the same pressure responsive means in connection with athletic shoes to indicate when the condition of excessive impact force is experienced by the wearer of the shoe. It is well known that runners and joggers experience very high impact forces on their feet and that such condition can lead to severe, sometimes permanent, bodily injury. In order to avoid this condition, athletic shoes include significant cushioning material between the inner sole and the outer sole for reducing the impact shock. Such cushioning material may comprise several layers of rubberized material, air cushions, gel material, etc.
The present invention discloses an arrangement wherein a strip of a rupturable medium containing dye in an encapsulated form is disposed in contact with the cushioning material, for instance at the location of the heel. When the impact force effective upon the rupturable medium exceeds a predetermined value, the medium ruptures and the escaping dye will stain the inner sole or, for instance, the sock of the person wearing the shoe. Therefore, a jogger or runner can be warned that the shoe has insufficient cushioning material, or that the cushioning material no longer is effective, having reached the end of its useful life. It will be apparent that a shoe construction of this type has significant benefits to joggers, runners, and sprinters, warning them of potential harm prior to actual and permanent injury.
One of the principal objects of this invention, therefore, is the provision of a new and improved athletic shoe construction.
Another important object of this invention is the provision of an athletic shoe construction having an impact sensing means in contact with the cushioning material normally provided in the shoe.
Another important object of this invention is the provision of an athletic shoe construction having an impact sensing means disposed in the shoe, the sensing means comprising a rupturable medium containing dye in an encapsulated form, said dye being released when a predetermined pressure acting thereupon is exceeded.
A further and important object of this invention is the provision of an athletic shoe having an impact sensing means comprising liquid dye in an encapsulated form, the dye being released when a predetermined pressure acting upon the sensing means is exceeded.
A still further object of this invention is the provision of an athletic shoe construction having impact sensing means in the form of strips of a rupturable medium, each strip containing dye of a different color and each strip being rupturable at a different predetermined impact force acting thereupon.
Further and still other objects of this invention will be more readily apparent from the following description when taken in conjunction with the accompanying drawings.